The group suspected of killing the Russian journalist Anna Politkovskaya was led by an ethnic Chechen organised crime boss, Russian authorities said today.

Yuri Chaika, the prosecutor general, also told a press conference that the killers included serving government officers.

"The group was headed by a leader of a Moscow criminal group of Chechen origin," Mr Chaika said. "We have evidence that this group took part in the killing of [the US journalist] Paul Klebnikov ... Unfortunately, this group included retired and acting interior ministry and FSB (Federal Security Service) officers."

Mr Klebnikov edited the Russian edition of the financial magazine Forbes. The 41-year-old was shot dead in July 2004 near his office in Moscow.

Earlier, prosecutors said they had arrested 10 people and would soon charge them in connection with the killing of Politkovskaya.

"We have made serious progress in the Politkovskaya murder investigation," the prosecutor general, Yuri Chaika, was quoted by the Itar-Tass news agency as saying.

"Ten people have been arrested in connection with this case and literally, in the very near future, they will be charged with carrying out this grave crime," he said.

The prosecutor told Vladimir Putin about the arrests during a meeting at the president's dacha just outside Moscow.

Politkovskaya's murder in October last year drew widespread international condemnation and prompted concern about press freedoms and the treatment of government opponents in Russia. She was a particularly fierce critic of human rights abuses in the Chechnya war.

Her last incomplete article, published last October, contained allegations of torture by pro-Russian Chechen security forces. Her newspaper, Noveya Gazeta, carried eyewitness accounts and photos of people with injuries said to have been sustained under torture.

Politkovskaya's colleagues from Noveya Gazeta cautiously welcomed the 10 arrests. Vyacheslav Izmailov, a friend and columnist on the paper, said few details of the arrests had been made public.

But he confirmed that the trail appeared to lead to Chechnya. "It's a very complicated case because it involves both those who ordered the murder and those who carried it out. There are Chechens (among those arrested). But not only Chechens," he told the Guardian.

Asked whether those arrested had definitely carried out her killing last October, he replied: "I don't know."

Dmitry Muratov, Noveya Gazeta's editor in chief, said the paper had been satisfied with the level of cooperation from Russian authorities since the murder last year. Asked about the arrests, he said: "I think this is serious. But I can't say more at the moment."

The suspects were arrested between August 15 and 23, he said. "There is no more information we can give at the moment, other to say that people have been arrested and that they include people from different nationalities. Right now they are under active investigation."

Mr Putin has said everything possible would be done to find and punish the killers of Politkovskaya, who was 48 when she was shot dead in the stairwell of her Moscow apartment.